1. Field of the Invention
The present invention relates to a method of fabricating a resin sealing type semiconductor device and a die assembly for fabricating the resin sealing type semiconductor device.
2. Description of Related Art
As shown by FIG. 18, in respect of a molded IC, that is, a resin sealing type semiconductor device which is sealed by a transfer molding process using a molding resin, when there is an element 43 which cannot be sealed by the resin block 40, the element 43 is arranged at a hollow portion 41 of the molded resin block 40. A lead frame 42 exposed to the hollow portion 41 and the element 43 are connected through wire bonding.
In that case, the following drawbacks may generally occur by which wire bonding may not be favorably carried out.
(A) Burrs of the molding resin adhere onto the exposed lead frame 42 after forming the molded resin block 40 by which wire bonding cannot favorably be performed.
(B) A die for forming the molded resin block 40 is brought into direct contact with the lead frame 42 during a molding operation. Therefore, a release agent adhered to the die is transferred to the lead frame 42 by which wire bonding cannot favorably be performed.
(C) The lead frame 42 is harmed since the die is brought into direct contact with the lead frame 42 in the molding operation by which excellent wire bonding cannot be performed.
In order to resolve the drawbacks as described above, the following techniques have been known.
(A) Favorable wire bonding regions are secured on the lead frame 42 by removing the burrs of the molding resin on the lead frame 42 and cleaning the release agent thereon after the molding operation as disclosed in, for example, Japanese Patent Application Laid-Open No. 6-85222.
(B) A protective film is previously formed at the wire bonding region on the lead frame 42 and the protective film is removed by etching after the molding operation thereby securing the excellent wire bonding region on the lead frame 42 as disclosed in, for example, Japanese Patent Application Laid-Open No. 6-302744.
However, when such a method is used, addition of steps is needed which gives rise to an increase in cost.